Embolism filter with self-deployable guidewire stop

ABSTRACT

An embolism filter adapted to selective stop an embolism filter along a length of guidewire, including a filter adapted to encircle a guidewire and at least one self-deploying stop attached to the filter and which selectively stops movement of said filter.

RELATED APPLICATIONS

This application claims the benefit under 35 USC § 119(e) of U.S.provisional application 60/400,801, filed on Aug. 5, 2002, thedisclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to devices for filtering emboliticmaterial from circulating blood.

BACKGROUND OF THE INVENTION

Embolitic material comprising calcium, intimal debris, pieces of anartheromatous plaque and/or thrombi, has the potential of migrating andcausing distal tissue damage, for example, stroke and/or myocardialinfarction. (See Topol, E. J. and Yadov, J. S., “Recognition of theImportance of Embolization in Athereosclerotic Vascular Disease”,Circulation 2000, 101:570.) Embolic material with the potential ofdistal tissue damage is often released during vascular interventionalprocedures, for example, stenting of an artheromatous region.

In response to the risk posed by released emboli during vascularintervention procedures, a mesh filter mounted on a specially adaptedguidewire may be introduced into a blood vessel to strain releasedembolitic material from the circulation, thereby reducing the risk ofdistal tissue damage. To deploy such a mesh filter, a specially designedguidewire, for example having a built-in stop, may be placed in theblood vessel so that the stop is just distal to the target area. Acollapsed filter is advanced along the guidewire until it is preventedfrom further advancement by the stop and opened so that it catchesdebris released from the target area.

Unfortunately, the specially designed guidewire is bulky and hard tomanipulate due, in part, to the incorporated stop and accuratepositioning of the filter is difficult once it has reached the guidewirestop. In addition, the use of a non-standard guidewire may requirereplacement or stocking of new catheterization sets.

Tsugita et al. in U.S. Pat. No. 6,361,971 B1 and US Applications2002/0095174 and 2002/0183782, the disclosure of which is incorporatedhereby in its entirety by reference, demonstrate filters and lockingmechanisms.

SUMMARY OF THE INVENTION

An aspect of some embodiments of the invention relates to an embolismfilter stop and method for its deployment, comprising a filter with oneor more self-deploying stops attached thereto that stop the filter atsubstantially any desired location along a length of guidewire.

According to an exemplary embodiment of the present invention, thefilter with its self-deploying stops can be deployed on guide wires in avariety of lengths and/or a variety of diameters. Alternatively oradditionally, different stop designs and/or materials may be used forspecific guidewires with specific properties, for example a flexibleand/or small gage wire that may be used in fetal surgery. It is aparticular feature of some embodiments of the invention, that the filtercan be deployed on a substantially smooth guide wire, with noprojections (where the filter is deployed) and/or with a uniformdiameter in such a section. However, the filter can also be deployedwith non-standard guide wires, for example, with a stepped or tapereddiameter or with stops, ignoring or utilizing these stops, depending onthe filter geometry.

In an exemplary embodiment, the at least one stop comprises isself-expanding, for example comprising a spring. Alternatively oradditionally, the at least one self-expanding stop comprises a cushionmade of, for example, a flexible rubber material. Additionally oralternatively, the at least one self-expanding stop comprises afluid-filled flexible compartment containing compressed fluid, forexample a gas that expands upon removal of a restrainer.

In an exemplary embodiment, a restrainer prevents the one or more stopsfrom prematurely contacting and locking to the guidewire. Upon reachingthe target tissue, the restrainer is pulled free and the stopself-deploys, fixing the filter in place. Optionally, the at least onestop comprises at least two stops that are, for example, symmetricallydisposed around said wire and/or apply symmetric and/or equivalent forcearound the wire. Alternatively or additionally, the stops provide equalamounts of motion (e.g., while expanding) on opposing sides of the guidewire and/or on axially spaced locations on the guidewire, so that theplacement of the filter is parallel to the guide wire. in someembodiments, an intentionally skewed placement of the filter may bedesirable.

In an alternative embodiment of the invention, the stop is notself-deploying but is integral to and mechanically coupled to the filterand is activated other than by the guidewire. In one example, the stopis a deforming and/or expandable element, such as an inflatable balloonhaving an inflation port to which an inflation hose is attached. In anexemplary embodiment, the port self-seals following inflation of theballoon and removal of the hose. If the balloon is elastic, it can alsobe restrained after inflation.

Optionally, the filter defines a front and rear boundary and the atleast one stop is connected to at least one of said boundaries. In anexemplary embodiment, the at least one stop is substantially containedbetween said boundaries, for example, so the overall length of thefilter is conserved, allowing the filter to be easily maneuvered in thevasculature. Alternatively or additionally, said at least one stopprojects beyond one or more of said boundaries.

An aspect of some embodiments of the invention relates to a filter thathas some axial freedom of motion relative to a guidewire, after it islocked in place on a guidewire. In an exemplary embodiment of theinvention, the filter deploys around a sleeve that travels along aguidewire, said sleeve having one or more stops shiftably attachedthereto. In an exemplary embodiment, the shiftable stops allow the openfilter to remain stationary in relation to the vascular environment evenif the guidewire is moved a small amount. In this manner, a shiftablestop limits movement of the open filter that may cause trauma to thesurrounding tissue, during for example, positional adjustments of aguidewire.

In an exemplary embodiment, the filter comprises one or more supportmembers, for example struts that support the filter membrane and/orslide along the sleeve during deployment and/or collapse of the filter.

In an exemplary embodiment, a sleeve capable of traveling along aguidewire, comprising one or more self-deploying stops, is used inconjunction with one or more devices deployed in the vasculature or inother hollow organs of the body, for example an arthroscopic fiber opticcable, brachytherapy device and/or a laser, using these devices as itsguidewire.

There is thus provided in accordance with an exemplary embodiment of theinvention, an embolism filter adapted to selectively stop an embolismfilter along a length of guidewire, said filter comprising:

a) a filter adapted to encircle a guidewire; and

b) at least one self-deploying stop attached to said filter and adaptedto selectively stop movement of said filter. Optionally, said at leastone stop comprises a spring. Optionally, said spring expands duringdeployment.

Alternatively or additionally, at least a portion of said stop isremovably attached to said filter.

In an exemplary embodiment of the invention, said at least one stopcomprises a cushion. Alternatively or additionally, said at least onestop comprises a chamber containing an expandable fluid. Optionally,said filter comprises a fluid release mechanism adapted to cause therelease of said expandable fluid.

In an exemplary embodiment of the invention, said at least one stop isadapted to be restrained from contacting said guidewire by at least onestop restrainer. Optionally, said at least one stop is adapted toself-deploy upon removal of said restrainer. Alternatively oradditionally, said restrainer comprises a material that changesconfiguration in response to contact with blood tissue.

In an exemplary embodiment of the invention, said at least one stopcomprises at least one inflatable member.

In an exemplary embodiment of the invention, said at least one stopcomprises at least two stops. Optionally, said at least two stops areradially disposed around said wire. Alternatively or additionally, saidat least two stops are adapted to apply substantially equivalent forceto said wire.

In an exemplary embodiment of the invention, said filter is adapted tocollapse within a restrictive cavity. Alternatively or additionally,said filter is adapted to self-expand upon exiting a restrictive cavity.Alternatively or additionally, said restrictive cavity comprises adelivery sheath. Optionally, said delivery sheath is removably coupledto said filter.

In an exemplary embodiment of the invention, at least one of said one ormore stops are adapted to move a limited distance along said filter.

In an exemplary embodiment of the invention, said filter comprises asleeve surrounding said one or more stops. Optionally, said stops do notextend beyond at least one end of said sleeve. Alternatively oradditionally, said filter is mounted on said sleeve and does not extendaxially beyond said sleeve.

There is also provided in accordance with an exemplary embodiment of theinvention, a method for stopping motion of a filter along a guidewirecomprising:

a) positioning a guidewire in a blood vessel;

b) advancing along said guidewire a filter having at least one stopattached thereto; and

c) allowing said stop to self-deploy and engage said guidewire, therebysecuring said filter along said guidewire. Optionally, the methodcomprises expanding said filter. Alternatively or additionally, themethod comprises, collecting particulate matter in the filter.Optionally, the method comprises collapsing said filter with saidcollected particulate matter. Optionally, the method comprises removingsaid filter with said collected particulate matter from said bloodvessel. Optionally, removing said filter comprises not removing saidguidewire.

There is also provided in accordance with an exemplary embodiment of theinvention, a guidewire stop, comprising:

a) a sleeve that slideably engages a guidewire; and

b) at least one self-deploying stop attached to said sleeve thatselectively stops movement of said sleeve along said guidewire.Optionally, the stop includes a vascular filter having front and rearboundaries wherein said sleeve is attached to at least one of saidboundaries. Optionally, said sleeve is extends beyond at least one ofsaid boundaries. Alternatively, said sleeve is substantially containedbetween said boundaries.

There is also provide din accordance with an exemplary embodiment of theinvention, an embolism filter adapted to selectively stop an embolismfilter along a length of guidewire, said filter comprising:

a) a filter adapted to encircle a guidewire; and

b) at least one deformable stop attached to said filter and adapted toselectively stop movement of said filter. Optionally, said stopcomprises an inflatable stop. Optionally, the filter comprises a removalsheath adapted to puncture said stop.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary non-limiting embodiments of the invention are described in thefollowing description, read with reference to the figures attachedhereto. In the figures, identical and similar structures, elements orparts thereof that appear in more than one figure are generally labeledwith the same or similar references in the figures in which they appear.Dimensions of components and features shown in the figures are chosenprimarily for convenience and clarity of presentation and are notnecessarily to scale. The attached figures are:

FIGS. 1-3 are cross sectional schematic views showing the operation ofan embolism filter and its self-deploying stops, in accordance with anexemplary embodiment of the invention;

FIGS. 4-6 are cross sectional schematic views of various embodiments ofguidewire sleeves with stops, in accordance with an exemplary embodimentof the invention;

FIG. 7 is a schematic view of a sleeve and guidewire stop in combinationwith a filter, in accordance with an exemplary embodiment of theinvention;

FIGS. 8A and 8B are schematic views of a shiftable filter stop, inaccordance with an exemplary embodiment of the invention;

FIG. 9 is a detailed cross sectional view of a filter during delivery ina blood vessel, in accordance with an exemplary embodiment of theinvention;

FIG. 10A is a detailed cross sectional view of a filter followingdeployment in a blood vessel, in accordance with an exemplary embodimentof the invention;

FIG. 10B is a partial detailed cross sectional view of the filter shownin FIG. 10A, in accordance with an exemplary embodiment of theinvention;

FIG. 10C is a head on view of the filter of FIG. 10A, in accordance withan exemplary embodiment of the invention; and

FIG. 11 is a detailed cross sectional view of a filter during removalfrom a blood vessel, in accordance with an exemplary embodiment of theinvention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Filter with Spring Stops

FIG. 1 is a cross sectional view of a filter 100 contained within adelivery sheath 150, in accordance with an exemplary embodiment of theinvention. In an exemplary embodiment, filter 100 comprises stops 180and 182 that are restrained from contacting a guidewire 102 by arestrainer 132. During positioning of filter 100, optional stabilizers152 that project from a sheath wall 120 press against filter 100 toadvance filter 100 along guidewire 102.

Filter 100 and/or stops 180 and 182 may be designed in a variety ofmaterials and shapes for example a range of guidewire diameters, forexample a range of 1:1.5, 1:2 or 1:4 or any smaller, intermediate orlarger ratio of diameters. Alternatively or additionally, in anyspecific design, filter 100 and/or stops 180 and 182 may be manufacturedto encompass a guidewire of a specific diameter. Guidewire diameters forwhich filter 100 and/or stops 180 and 182 can be designed include, forexample:

i) small gage flexible guidewires for use in peripheral vasculature, forexample having a diameter of 0.014, 0.018, 0.032 or 0.035 inches;

ii) guidewires designed for coronary surgery, for example having adiameter of 0.014.

iii) specially designed guidewires designed for coronary interventionsand/or fetal surgery, having diameters smaller than 0.014, greater than0.035 and/or having non-standard diameters between 0.014 and 0.035inches.

In an exemplary embodiment, restrainer 132 has a passage 134 that ridesalong wire 102 and permits movement of filter 100 distal to the targettissue location.

In an exemplary embodiment, a front boundary 122 of delivery sheath maybe tapered to facilitate easy movement through the vasculature.Additionally or alternatively, front boundary 122 may be curved intowards wire 102. Optionally, front boundary 122 comprises a flexiblematerial so that it allows filter 100 to exit in spite of beingunvaccinated.

In an exemplary embodiment, front boundary 124 of a sleeve wall 184 istapered to ease advancement of filter 100 through the vasculature.Additionally or alternatively, a rear boundary 126 is tapered tofacilitate retreat of filter 100 through the vasculature.

Optionally, stops 180 and/or 182 are contained internal to wall 184, forexample near or at front boundary 124 and/or rear boundary 126 of filter100, so the overall length of filter 100 is conserved. Having a shorterprofile associated with internally contained stops 180 and/or 182, mayassist filter 100 in maneuvering in the vasculature. Alternatively oradditionally, stops 180 and/or 182, within wall 184, project beyondfront boundary 124 and/or rear boundary 126 of filter 100. In anexemplary embodiment, stops 180 and/or 182 comprises springs, forexample a spring steel, or resilient plastic.

Deployment of stops 180 and 182 may be actuated, for example, by usingrestrainer 132 that is remotely controlled, for example using an RFsignal to cause its displacement and/or dissolution. Alternatively,other methods of actuation of stops 180 and 182 are contemplated, forexample, restrainer 132 may dissolve or fall apart in the presence ofblood or under the action of RF radiation or ultrasonic radiation.

In FIG. 2, delivery sheath 150 remains around filter 100 and stabilizers152 press against filter 100 while restrainer 132 is pulled away fromstops 180 and 182, using a restrainer cable 130 to pull restrainer 132in a direction 140. In an exemplary embodiment, restrainer 132 has alength of between 1-4 centimeters. Optionally restrainer 132 is lessthan 1 or 0.5 centimeter in length when used, for example, with smallstops 180 and/or 182, designed for fetal and/or pediatric procedures.Optionally, restrainer 132 has a length of greater than 4 centimeterswhen used, for example, with stops 180 and/or 182, for example, that are3 or 4 centimeters or more in length for use when filter 100 is larger,for example where large amounts of particulate matter is anticipatedthat cannot be contained by a smaller filter. Restrainer 132 isoptionally flexible in bending, even if it is not compressible, forexample it may be segmented into narrow rings that are interconnected bya soft material.

Optionally, restrainer 132 is removed from contact with stops 180 and/or182 by pulling restrainer cable 130 so that restrainer 132 shiftsapproximately 1 centimeter with respect to stops 180 and/or 182. Inpediatric and/or large vessel use, when smaller or larger stops 180and/or 182 are used, restrainer 132 may require less than 1 centimeteror greater than 1 centimeter of movement to allow stops 180 and/or 182to expand.

With restrainer 132 removed, stops 180 and 182 expand to contactguidewire 102 thereby fixing filter 100 in place along guidewire 102.With filter 100 fixed in place, stops 180 and 182 stabilize filter 100so that sheath 150 can be pulled away from filter 100 as seen, forexample, in FIG. 3.

With delivery sheath 150 removed from filter 100, a porous filtermembrane 190 expands, for example as a result of blood flow pressureagainst it, to act as a filter, serving to strain particulate matterfrom the blood. Alternatively or additionally, filter 190 is made ofresilient material that self-expands as it is freed of delivery sheath150.

Optionally, delivery sheath 150 is moved in a direction 142 againstfilter membrane 190, thereby causing filter membrane 190 to collapse.With membrane 190 collapsed, filter 100, guide wire 102 and sheath 150are removed from the blood vessel. Using a guidewire of uniform diameterand/or without projections to aid in positioning filter 100, ispotentially advantageous as any number of additional devices, forexample stents, can be interchangeably used with any guidewire 102 andany filter 100. Stents of a variety of diameters, for example, can bestocked separately of guidewires 102 and/or filters 100 of differentdiameters. This reduces inventory costs associated with packaging eachdiameter of stent in multiple packages, each package containing adifferent diameter and/or design of guidewire 102 and/or filter 100.

Sleeve with Inflatable Stops

In an alternative stop mechanism to spring stops 180 and 182, FIG. 4shows a cross sectional view of a sleeve stop 400 having an outer wall402 from which one or more inflatable balloon stops 480 and 482 project.In an exemplary embodiment, sleeve is delivered to a target site and aninflation hose 484 connected to one or more inflatable balloon stops 480and/or 482 is used to transfer fluid into balloons 480 and/or 482thereby causing their expansion. Balloons 480 and/or 482 expand untilthey contact wire 102, thereby preventing further movement of sleevestop 400. In an exemplary embodiment, a hose attachment port 486,self-seals following inflation of balloons 480 and/or 482 and removal ofhose 484.

In an exemplary embodiment, fluid contained in balloons 480 and 482 isbiologically inert so that its introduction into the blood stream willnot cause any untoward sequella. In an exemplary embodiment, sleeve stop400 may be removed from the blood vessel without removing guide wire102, for example using the following technique:

1. A sheath having one or more sharp projections at its leading edge,for example, is fed along guidewire 102 until its leading edge contactsballoons 480 and/or 482.

2. The sheath is pressed against sleeve stop 400 so that the one or moresharp projections puncture balloon 480 and/or 482, allowing thebiologically inert fluid within to escape harmlessly into the bloodstream.

3. A retrieval sheath is introduced along guide wire 102 and sleeve stop400 is pulled into the retrieval sheath, using methods well known in theart, for example; Optionally, the retrieval sheath includes one or moreretractable hooks that engage and pull back the filter portion, so thatit collapses. Alternatively or additionally, the retrieval sheathincludes a cooling material, which when applied to a filter made of asuitable shape memory material causes the filter to change its shape toa collapsed filter. The retrieval sheath containing sleeve stop 400 isremoved from the blood vessel while guidewire 102 is optionally left inplace. The retrieval sheath may be provided before balloons 480 and 482are deflated.

Alternatively or additionally, inflation hose 484 is coupled to balloons480 and/or 482 so that removal of hose 484 leaves an opening in balloons480 and/or 482. Hose 484 is left in place following expansion ofballoons 480 and/or 482 until, for example, sleeve stop 400 requiresremoval.

To remove sleeve stop 400 without removing guidewire 102, the followingprocedure is optionally followed:

1. Inflation hose 484 is pulled so that it disconnects from inflatableballoon stops 480 and/or 482. Disconnection of hose 484 allows thebiologically inert fluid to escape harmlessly into the blood stream andballoons 480 and/or 482 deflate.

2. Sleeve stop 400 is pulled into a retrieval sheath and removed asnoted above in previous step 3.

Sleeve with Expanding Cushion Stops

In another alternative stop mechanism to spring stops 180 and 182, FIG.5 shows a cross sectional view of a sleeve stop 400. Sleeve stop 400 hasouter wall 402 from which one or more self-expanding cushions, 580and/or 582 are restrained from contacting wire 102 by restrainer 132. Inan exemplary embodiment, after sleeve stop 400 reaches its target area,restrainer 132 is pulled away from sleeve 400 using restrainer cable130, thereby allowing cushions 580 and/or 582 to deploy and fix sleeve400 in place. These cushions may be formed, for example, out of siliconepolymers.

Alternatively or additionally, cushions 580 and/or 582 compriseexpanding absorbent materials that, for example, absorb intravascularfluid and expand. Restrainer 132, for example, compresses cushions 580and/or 582 so they are prevented from absorbing fluid until they arefreed from restrainer 132.

With cushions 580 and/or 582 comprising fluid-absorbing embodiments,restrainer 132, for example, may comprise a layer of materials 544and/or 546 that interfaces with cushions 580 and/or 582 to prevent fluidfrom being absorbed. Upon displacement of materials 544 and/or 546, forexample with removal of restrainer 132, fluid absorption by cushions 580and/or 582 subsequently takes place.

Compressed Gas Stops

FIG. 6 is an alternative embodiment of self-deploying sleeve stop 400having outer wall 402 from which project one or more flexiblecompartments 680 and/or 682 containing compressed gas. In an exemplaryembodiment, restrainer 132 is removed from flexible compartments 680and/or 682, so that the compressed gas within expands, causing flexiblecompartments 680 and/or 682 to expand and contact guidewire 102.

Optionally, compartments 680 and/or 682 contain compressed gas canisters690 and 692 respectively that are restrained from expanding byrestrainer 132. Upon removal of restrainer 132, for example, thecompressed gas breaks through a weak spot 694 in canister 690 and/or aweak spot 696 in canister 692, allowing compressed gas to escape andexpand compartments 680 and/or 682.

Alternatively or additionally, 694 and 696 comprise openings incanisters 690 and 692 respectively. In an exemplary embodiment,restrainer 132 press the walls of compartments 680 and/or 682 compressagainst openings 694 and 696 so they remain sealed. Upon removal ofrestrainer 132, walls of compartments 680 and/or 682 remove fromopenings 694 and 696, allowing gas to expand into compartments 680and/or 682.

Membranous Filter With Guide Stop Sleeve

FIG. 7 is a sleeved guidewire stop and filter 700, in accordance with anexemplary embodiment of the invention, comprising outer wall 402 withstops 180 and 182, in accordance with an exemplary embodiment of theinvention.

In an exemplary embodiment, porous membrane filter 190 has one or moreliving (or other type) hinge attachments 720 to outer wall 402, allowingfilter 190 to pivot open or closed in relation to wall 402, duringexpansion and/or collapse. The hinge attachment of porous filter 190 towall 402 may comprise a variety of materials, for example, differentformulations of resilient plastics. Alternatively or additionally,attachment of porous filter 190 to wall 402 may comprise alternativedesigns, for example, one or more hooks passing through one or moreeyes.

In an exemplary embodiment, porous membrane 190 has one or more struts710 and/or 712 attached to a circumferential ring 722. Struts 710 and/or712 support porous membrane 190 and circumferential ring 722 slidesalong outer wall 402 during deployment and/or collapse of struts 710and/or 712. For example, as a filter surface 740 moves in a direction732, strut 710 and/or circumferential ring 722 move in a direction 730,so that filter 700 assumes the deployed-configuration shown.

In an exemplary embodiment, movement of strut 710 in direction 730and/or movement of filter surface 740 in direction 732 is automatic whenthey exit from sheath 150. Alternatively or additionally, anoperator-controlled mechanism, for example a membrane filter deployercable 750 is pulled in a direction 752 so that struts 710 and/or 712move radially outward from guidewire 102 until membrane 190 is in thedeployed position.

In an exemplary embodiment, following expansion, filter 190 serves totrap particulate matter, for example, one or more of pieces of anartheromatous plaque, thrombi, and/or gas. Following completion of theprocedure, filter 190 is collapsed and removed, along with theparticulate matter, for example, with guide wire 102.

In an exemplary embodiment, porous membrane 190 and/or struts 710 and/or712 contact the inner surface of blood vessel 864 to form a seal and/orsubstantially span blood vessel 864 so that at least a substantialamount, if not all, blood passing through blood vessel 864, is filteredby membrane 190.

Blood vessel size may be from 2-8 millimeters in diameter, and even lessthan 2 millimeters or greater than 8 millimeters in certain areas and/orindividuals. Optionally, to accommodate this range in blood vessels,different embodiments of porous membrane 190 and/or struts 710 and/or712 may exhibit different degrees of radial expansion or may bepartially deployed.

For example, in vessels 864 with a smaller diameter, struts 710 and/or712 may deploy so they are not maximally expanded with respect toguidewire 102, while in larger blood vessels, struts 710 and/or 712, forexample, may approach their maximal expansion configuration.

Filter with Shiftable Stops

FIG. 8A is a filter 800 with shiftable guidewire stop 180, mounted on ashift platform 810 and guidewire stop 182, mounted on a shift platform812. Shiftable stops 180 and/or 182 shiftably secure sleeve wall 184 inrelation to guidewire 102. In this and other embodiments it should benoted that platforms 810 and 812 may be a single tubular platform andthat stops 180 and 182 maybe a single tubular stop. Use of separateelements, however, especially in this embodiment, may allow some extrafreedom in accommodation of shifting and/or other movement (e.g.,bending) of guide wire 102.

FIG. 8B shows filter 800 remaining stationary relative to blood vessel864, while platform 812 and guidewire 102 move a small amount in adirection 824.

The degree of allowed shifting may depend, for example, on an innergeometry of wall 184, for example, if rails are provided for theplatforms and/or if stops are provided for the platforms, for example atthe ends of wall 184.

In an exemplary embodiment, shift platform 810 shifts in relation tosleeve wall 184, for example one centimeter in direction 824, or onecentimeter in direction 820. Greater or smaller amounts of shifting maybe allowed, for example, between 2 and 5 mm, or greater or smalleramounts. Filter 800 is optionally designed to shift in a symmetricalmanner, once deployed.

Alternatively or additionally, filter 800 may be used in an environmentwhere shifting in direction 820 is anticipated to be different thanshifting in direction 824. For example where multiple stents are beingplaced one after the other, filter 800 may need to shift more indirection 820 than in direction 824. Alternatively or additionally toaxial shifting, rotational shifting may be allowed, for example byproviding rotational freedom (optionally with one or more stops) betweenplatform 810 and sleeve 184.

In an exemplary embodiment, shiftable stops 180 and/or 182 are confinedin their movement, for example, within a rear sleeve boundary 830 and/ora front sleeve boundary 834. Changing the distance between boundaries830 and 834, increases or decreases the excursion available to stops 180and 182 in relation to wall 184.

Optionally filter 800 may be designed so that sleeve wall 184 has agreater excursion than plus or minus one centimeter in relation toplatforms 810 and 812, for example in large diameter blood vessels.Alternatively or additionally filter 800 may be designed so that sleevewall 184 has a smaller excursion in relation to platforms 810 and 812,for example in small diameter blood vessels in fetal applications. In anexemplary embodiment, platforms 810 and 812, for example, comprise aring that is shiftably mounted against sleeve wall 184.

Alternatively or additionally to free shifting, platforms 810 and 812are elastically attached to sleeve wall 184, for example to absorb shockcaused by sudden movement of guidewire 102 (and then optionally realignthe filter in accordance with the new guidewire position), or toencourage smaller amounts of shifting.

Referring back to FIG. 7, to show a potential advantage of using ashiftable filter, upon deployment of shiftable filter 700, filtermembrane 190, for example, contacts a blood vessel wall 864, forexample, around its perimeter. Pressure on filter 700 in directions 824and/or 820, for example due to movement of guidewire 102, may causemovement of filter 700, so that filter membrane 190 scrapes blood vesselwall 864, possibly causing damage to blood vessel. Alternatively,distortion of the filter may occur, which may also be undesirable.

By allowing movement of shiftable filter 800 as sleeve 184 moves inrelation to shift platforms 810 and 812, shiftable filter 800 remainsstationary with respect to blood vessel wall 864 even when there ismovement pressure in directions 820 and/or 824. By limiting movement ofshiftable filter 800 with respect to blood vessel wall 864, trauma towall 864 is possibly reduced and/or eliminated.

Filter Structure Detail

FIG. 9 is a detailed cross sectional view of a filter 900 and stops 180and 182 during delivery in a blood vessel 864, in accordance with anexemplary embodiment of the invention. In an exemplary embodiment, stops180 and/or 182 are limited in movement by a forward limiter 932 and arear limiter 942. Stops 180 and/or 182, for example, are attached tolimiters 932 and 942. Limiters 932 and/or 942 may be fixed to wall 402,slideably attached to wall 402 and/or slideably attached to wall 402 forexample so that limiters 932 and/or 942 move only under a relativelylarge displacement force.

In an exemplary embodiment, delivery sheath 150 has an opening 948 thatallows filter 900 to be deployed on a guidewire 902 using a rapidexchange and/or a monorail technique. In a monorail technique, guidewire902 does not require excursion along the length of delivery sheath 150,for example two meters or more.

In an exemplary embodiment, to facilitate rapid deployment, sleeve 150,for example has curved section 922 that curves toward guide wire 902.Curved section 922, for example, may be advantageous in that it aidssheath 150 in passing easily through blood vessel 864 without scrapingwalls of blood vessel 864.

Alternatively or additionally, curved section 922 edges may be beveledalong the front boundary. Beveling the edges of curved section 922 maybe advantageous in that it aids in placement of filter 900 withoutcausing trauma to surrounding tissue. Outer wall 402 optionally containscurved tip 920 to additionally aid in placement of filter 900 withoutcausing tissue trauma. Section 922 and/or tip 920 optionally sealagainst guidewire 902, to prevent blood flow between them.

In an exemplary embodiment, filter 900 has a curved section 920 thatallows movement of filter 900 against blood vessel 864 without causingtrauma during a rapid exchange technique.

In an exemplary embodiment, struts 910 are collapsed within deploymentsheath 150, along with filter 190 that is attached to circumferentialring 722.

FIG. 10A is a detailed cross sectional view of filter 900 followingexpansion of stops 180 and 182 and removal of delivery sheath 150. Uponremoval of delivery sheath 150, for example, struts 910 and/or filtermembrane 190 have expanded radially outwardly in accordance with anexemplary embodiment of the invention.

In an exemplary embodiment, rings 932 and 942 are fixed in place alongwall 402, while ring stops 180 and 182, for example, deform underpressure from restrainer 132 (FIG. 9). Deformation of stops 180 and 182,for example, may comprise undulations along stops 180 and 182. Uponremoval of restrainer 132, stops 180 and 182 expand to a final stateshown schematically in FIG. 10A.

FIG. 10B is an alternative embodiment of stops 180 and 182 shown in FIG.10A Filter 900 comprises ring 942 that is fixed in place along wall 402and ring 932 that is slideably connected to wall 402. In an exemplaryembodiment, upon removal of restrainer 132, spring stops 180 and 182change their profile. To accommodate this change in profile, ring 932slides along wall 402, for example leaving gaps 1010 and 1012respectively.

Porous membrane 190, for example, is made of materials having pores of200 microns in diameter, though it could have pores of between 20 and250 microns, depending upon anticipated type and size of debris.

In delicate fetal procedures, for example fetal hydrocephalic shuntplacement, pore size may be below 20 microns, while in retrieval ofembolitic material from the lungs pores may be above 250 microns indiameter.

In an exemplary embodiment, porous membrane has an internal volume of0.3 cubic centimeters or greater, for example within the area definedbetween porous filter 190 and wall 402, allowing filter 900 to trapsignificant amounts of particulate debris. Alternatively oradditionally, porous membrane has an internal volume of 0.3 cubiccentimeters or less, for example, when used in blood vessels of smallersize, and/or in procedures where less debris is generated.

FIG. 10C is a detailed head on view of 900 filter of FIG. 10A, inaccordance with an exemplary embodiment of the invention, showing stops1080 and 1082 in addition to stops 180 and 182 so that guidewire 902 issurrounded by stops 180, 182, 1080 and 1082.

FIG. 11 is a detailed cross sectional view of filter 900 during removalfrom blood vessel 846 following deployment of a stent 1140, inaccordance with an exemplary embodiment of the invention.

Removal sheath 1110 is placed on guidewire 902, for example throughopening 1048, and moved along guidewire 902, through guide catheter 940until its front boundary contacts strut 910. As sheath 1110 contactsstrut 910, strut 910 moves radially toward guidewire 902 whilecircumferential ring 722 moves toward and/or past curved tip 920.

In an exemplary embodiment, space 1124 maintains a volume suitable fortransporting the particulate and/or gaseous debris during removal offilter 900 from blood vessel. With filter 900 collapsed and partially ortotally contained within sheath 150, filter 900 and/or sheath 150,and/or guidewire 902 are pulled through stent 1140, and out of bloodvessel 846. Filter 900 is optionally designed to resist deformity duringremoval so that it fully removes any particulate it captured during itsdeployment in vessel 864.

An Exemplary Surgical Procedure

In an exemplary embodiment, filter 900 is deployed in and removed from ablood vessel in the following manner:

1. An entry portal is made into an accessible blood vessel 846, forexample the femoral artery.

2. A guide catheter and/or dedicated sheath 940 is fed from the femoralartery to the target area.

3. Guide wire 902 is fed through guide catheter 940 into blood vessel864 past, for example, an artheromatous plaque 916 (FIG. 9).

4. Sheath 150, containing filter 900 in the collapsed state, is threadedonto guidewire 902 and moved along blood vessel 864 using sheath 150 topush it forward.

5. Upon reaching or passing the target site, restrainer 132 is removedso that stops 180 and/or 182 deploy to lock filter 900 on guide wire902.

6. Sheath 150 is removed from filter 900 and filter 900 expands so thatmembrane 190 spans all or part of the cross sectional diameter of bloodvessel 864 and sheath 150 is pulled out of vessel 846, as seen in FIG.10A.

7. When filter 900 is used in conjunction with a stenting procedure, forexample, guide catheter and/or dedicated sheath 940 is fed overguidewire 902 until it reaches the target area and stent 1140 isdeployed and anchored in blood vessel 864 while embolitic material iscaught by open filter 900 as seen in FIG. 10C, for example downstream ofstent 1140.

8. As seen in FIG. 11, following completion of the procedure, removalsheath 1110 is optionally fed onto guidewire 902 and pushed forward inblood vessel 846 until its front boundary contacts struts 910.

9. Sheath 1110 is pressed against struts 910 to cause them to collapseradially and sheath 1110 along with filter 900 and guide wire 902 areremoved from blood vessel 864.

Exemplary Specifications

Referring to FIG. 9, rapid exchange guidewire 902 used in a rapidexchange technique, for example, may be flexible anywhere along itslength, for example at a flexed section 952 as filter 900 moves alongguidewire 902.

To secure filter 100 in place, stops 180 and 182 are designed to eachdeliver, for example, 100 to 500 grams of force against guide wire 102.However, stops 180 and 182 may be designed to deliver a force less than100 grams for used in special situations, for example where thedisplacement force is extremely low, for example in peripheral veins.Alternatively or additionally, stops 180 and 182 may be designed todeliver a force greater than 500 grams, for example, in patients withhigh blood flow speed, where released emboli are likely to have largemass and/or when a more slippery guide wire is anticipated.Alternatively or additionally, a force greater than 500 grams may berequired when guidewire 102 comprises smooth materials that do notprovide a friction finish to which stops 180 and 182 secure under lowerpressure.

Stops 180 and 182, for example, may be manufactured from resilientmaterial such as surgical grade spring steel. For example, the wholewall 184 including the stops may be cut (e.g., using a laser or othermeans known in the at) from a sheet of steel or other biocompatiblemetal, such as titanium, or a nickel titanium alloys. Depending on theimplementation, it may be desirable that the filter, body and/or stopsbe formed of plastic, elastic and/or super elastic materials.

Stops 480 and 482 (FIG. 4), 580 and 582 (FIG. 5), and 680 and 682 (FIG.6), may be, for example, manufactured from surgical grade polyethylene,nylon and/or terephthalate and/or other flexible, surgical-gradematerials suitable for use in the vasculature.

Two stops, 180 and 182 are shown, but filter 100 may comprise less ormore stops, for example, depending upon the diameter of guidewire 102,the material from which guidewire 102 is manufactured and/or the designof filter 100.

In an exemplary embodiment, stops 180 and 182 are radially disposedaround wire 102, for example so they apply equivalent radial pressure,that will not cause deformation to filter 100. Applying even pressureallows stops 180 and 182 to be positioned between boundaries 122 and 124(FIGS. 1-3) without distorting the architecture of filter 100 and/orwall 184. Optionally, two or more axially displaced stops (relative tothe guidewire) or sets of stops may be used.

In an exemplary embodiment of the present invention, sleeve stop 400(FIGS. 4-6) is used in conjunction with any number of devices that aredelivered into the vasculature. Such devices, for example, may includeablation lasers and/or catheter balloons that are used to ablateintravascular plaques, stents for restoring and/or maintaining patencyof blood vessels.

Alternatively or additionally, such devices may include a variety ofinstrumentation including an arthroscopic tip, laparoscopic tools,and/or artheromatous shavers that are often used in vascular procedures.

While the invention has been described with respect to a limited numberof embodiments, it will be appreciated that many variations,modifications and other applications of the invention may be made. Inparticular, features from one embodiment may be combined with featuresof another embodiment, in accordance with some embodiments of thepresent invention.

A variety of values have been utilized to describe the inventionincluding, diameters, lengths and types of materials for the variousfilters, sleeves and/or stops. Although a variety of values and/ormaterials have been provided, it should be understood that these couldvary even further based upon a variety of engineering principles,materials, intended use and designs incorporated into the invention.

It should be appreciated that different features may be combined indifferent ways. In particular, stop sleeve may be utilized with otherinstruments and/or devices used in the vasculature and may be modifiedin shape, size and/or materials to be ergonomically and engineeringlycompatible with the specific usage.

Hence, not all the features, shapes and/or dimensions shown above in aparticular embodiment may be necessary in every similar exemplaryembodiment of the invention. The particular geometric forms andmeasurements used to illustrate the invention should not be consideredlimiting the invention in its broadest aspect to only those forms.Although some limitations are described only as method or apparatuslimitations, the scope of the invention also includes apparatus designedto carry out the methods of using the apparatus.

Also within the scope of the invention are surgical kits, for example,kits that include sets of delivery systems, guidewires, filters and/orself-deploying stops. Optionally, such kits also include instructionsfor use. Measurements are provided to serve only as exemplarymeasurements for particular cases, the exact measurements applied willvary depending on the application. When used in the disclosure and/orclaims, the terms “comprises”, “comprising”, “includes”, “including” orthe like mean “including but not limited to”.

A person skilled in the art will appreciate that the present inventionis not limited by what has thus far been described. Rather, the scope ofthe present invention is limited only by the following claims.

1. An embolism filter adapted to selectively stop an embolism filteralong a length of guidewire, said filter comprising: a) a filter adaptedto encircle a guidewire; and b) at least one self-deploying stopattached to said filter and adapted to selectively stop movement of saidfilter.
 2. The filter according to claim 1, wherein said at least onestop comprises a spring.
 3. The filter according to claim 2, whereinsaid spring expands during deployment.
 4. The filter according to claim2, wherein at least a portion of said stop is removably attached to saidfilter.
 5. The filter according to claim 1, wherein said at least onestop comprises a cushion.
 6. The filter according to claim 1, whereinsaid at least one stop comprises a chamber containing an expandablefluid.
 7. The filter according to claim 6, including a fluid releasemechanism adapted to cause the release of said expandable fluid.
 8. Thefilter according to claim 1, wherein said at least one stop is adaptedto be restrained from contacting said guidewire by at least one stoprestrainer.
 9. The filter according to claim 8, wherein said at leastone stop is adapted to self-deploy upon removal of said restrainer. 10.The filter according to claim 8, wherein said restrainer comprises amaterial that changes configuration in response to contact with bloodtissue.
 11. The filter according to claim 1, wherein said at least onestop comprises at least one inflatable member.
 12. The filter accordingto claim 1, wherein said at least one stop comprises at least two stops.13. The filter according to claim 12, wherein said at least two stopsare radially disposed around said wire.
 14. The filter according toclaim 12, wherein said at least two stops are adapted to applysubstantially equivalent force to said wire.
 15. The filter according toclaim 1, wherein said filter is adapted to collapse within a restrictivecavity.
 16. The filter according to claim 1, wherein said filter isadapted to self-expand upon exiting a restrictive cavity.
 17. The filteraccording to any of claim 15, wherein said restrictive cavity comprisesa delivery sheath.
 18. The filter according to claim 17 wherein saiddelivery sheath is removably coupled to said filter.
 19. The filteraccording to claim 1, wherein at least one of said one or more stops areadapted to move a limited distance along said filter.
 20. The filteraccording to claim 1, comprising a sleeve surrounding said one or morestops.
 21. The filter according to claim 20, wherein said stops do notextend beyond at least one end of said sleeve.
 22. The filter accordingto claim 20, wherein said filter is mounted on said sleeve and does notextend axially beyond said sleeve.
 23. A method for stopping motion of afilter along a guidewire comprising: a) positioning a guidewire in ablood vessel; b) advancing along said guidewire a filter having at leastone stop attached thereto; and c) allowing said stop to self-deploy andengage said guidewire, thereby securing said filter along saidguidewire.
 24. The method according to claim 23, comprising expandingsaid filter.
 25. The method according to claim 23, comprising collectingparticulate matter in the filter.
 26. The method according to claim 25,comprising collapsing said filter with said collected particulatematter.
 27. The method according to claim 26, comprising removing saidfilter with said collected particulate matter from said blood vessel.28. The method according to claim 27, wherein removing said filtercomprises not removing said guidewire.
 29. A guidewire stop, comprising:a) a sleeve that slideably engages a guidewire; and b) at least oneself-deploying stop attached to said sleeve that selectively stopsmovement of said sleeve along said guidewire.
 30. The guidewire stopaccording to claim 29, including a vascular filter having front and rearboundaries wherein said sleeve is attached to at least one of saidboundaries.
 31. The guidewire stop according to claim 30, wherein saidsleeve is extends beyond at least one of said boundaries.
 32. Theguidewire stop according to claim 30, wherein said sleeve issubstantially contained between said boundaries.
 33. An embolism filteradapted to selectively stop an embolism filter along a length ofguidewire, said filter comprising: a) a filter adapted to encircle aguidewire; and b) at least one deformable stop attached to said filterand adapted to selectively stop movement of said filter.
 34. A filteraccording to claim 33, wherein said stop comprises an inflatable stop.35. A filter according to claim 34, comprising a removal sheath adaptedto puncture said stop.